Deep brain stimulation (DBS) is an established neuromodulation therapy for the treatment of movement disorders, and has been shown to improve cardinal motor symptoms of Parkinson's Disease (PD), such as bradykinesia, rigidity, and tremors. These improvements generally occur within a few minutes of initiation of stimulation, and disappear within a similar timeframe after stimulation is discontinued. DBS may include using tonic stimulation to deliver high-frequency isochronal electrical pulses (e.g., at a pulse frequency of 130-180 Hertz (Hz) with a pulse width of 20-200 microseconds) through a single contact electrode implanted in the Basal ganglia thalamo-cortical “motor circuit” of the brain.
In brain activity, abnormal synchronization of neuronal activity is an indicator of various movement disorders, such as PD. Studies have shown that PD is associated with increase oscillations in the beta band, which has been associated with bradykinesia and rigidity. Further, research has suggested that such abnormal synchronization may be disrupted by delivering short sequences of stimulation pulses through different electrodes activated at different times in random order. This may provide sustained amelioration of rigidity and bradykinesia, especially after multiple stimulation sessions. However such random stimulation may not be as effective as tonic stimulation, and may not ameliorate tremors, which may be severely disabling for a patient.